Lake Forest Dentist: Two Types of Smiles

Often, in the name of politeness, we find ourselves faking a smile. People may force a smile during a bad joke or to mask a bad mood. For years, researchers believed one could easily distinguish a genuine smile from a fake one. In fact, many considered it impossible to fake a genuine smile, also known as Duchenne smile. But recent studies have shown people may be able to fake very real smiles. In today’s blog, your Lake Forest dentist, Dr. James Fondriest, explains the science behind the Duchenne smile.

Recognizing a True Smile

In the 19th century, French physician Guillaume Duchenne identified two distinct types of smiles. According to Duchenne, a genuine smile involves a patient raising the corners of the mouth, known as the zygomatic major muscle, and raising the cheeks to form crow’s feet around the eyes. Combined, the contraction of these two muscles reveals a truly positive smile. This type of smile is generally known as a Duchenne smile. The other type of smile involves a patient only raising the zygomatic major muscle. Duchenne considered this a forced, or fake, smile.

New Research

Until recently, most experts concluded that a person simply couldn’t fake a Duchenne smile. Then, in 2009, the University of Geneva released a study that showed many people could easily replicate a genuine looking Duchenne smile. In 2012, Northeastern graduate student Sarah Gunnery and her colleagues further debunked the Duchenne smile. One part of the study involved showing participants photographs a Duchenne smile and a fake smile. The participants were asked to mimic both smiles. The results showed that 71% of participants could successfully fake a Duchenne smile. In addition, 69% had no difficulty replicating a forced smile.